body{
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  min-height: 100vh;
}

h2{
  text-align: center;
  font-family: sans-serif;
  margin-bottom: 4rem;
  margin-top: 4rem;
}
h2 span{
  display: inline-block;
}
h2>span::before,h2>span::after{
  display: block;
  content: "";
  width: 100%;
  height: 0.15rem;
  background-color: black;
}
.special_span{
  position: relative;
}
.special_span::before{
  top: -0.3rem;
}
.special_span::after,.special_span::before{
  position: absolute;
  left: calc(100%);
  bottom: -0.3rem;
  display: block;
  content: "";
  transform: rotate(45deg);
  width: 0.5rem;
  height: 0.5rem;
  background-color: black;
}
.introduce_box{
  transform-style: preserve-3d;
  perspective: 1000px;
  display: flex;
  justify-content: space-around;
  width: 70vw;
  margin: 0 auto;

}
.card{
  display: flex;
  flex-direction: column;
  width: 70vw;
  min-height: 24vw;
  transition: transform 0.1s;
  cursor: pointer;
}
/* 
这里区分第一个container和第二个
*/
.card:nth-child(1){
  transform:  rotateX(45deg) scale(0.9,0.9);
  background-color: rgba(0, 255, 149, 0.76);
}
.card:nth-child(2){
  background-color: rgba(224, 167, 62, 0.76);
  transform:  rotateX(45deg) scale(0.9,0.9);
}
.card:nth-child(3){
  transform: rotateX(45deg) scale(0.9,0.9) ;
  background-color: rgba(255, 0, 80, 0.76);
}

/* 强制用动画渲染 */

@keyframes rotateZEnter {
  from {
    transform:  rotateY(60deg) ;
  }
  to {
    transform: none ;
  }
}

@keyframes rotateZLeave {
  from {
    transform: none ;
  }
  to {
    transform:  rotateY(60deg) ;
  }
}

@keyframes rotateXEnter {
  from {
    transform: rotateX(45deg)  ;
  }
  to {
    transform: none ;
  }
}

@keyframes rotateXLeave {
  from {
    transform: none ;
  }
  to {
    transform: rotateX(45deg)  ;
  }
}


/* 
这里区分第一个container和第二个
*/
.card h3{
  margin: 0;
  padding: 0.5rem 1rem;
  align-self: center;
}
.card p{
  width: 60%;
  margin-left: auto;
  margin-right: auto;
}
.ca_img{
  width: 60%;
  padding: 20% 0;
  margin: 2% auto;
  /* background-color: aqua; */
}